The purpose of this project is to develop methods for the extraction, isolation, and characterization of polypeptides with the property of conferring the transformed phenotype on normal indicator cells. These purified transforming growth factors (TGFs) will then form the basis for investigation of the mechanism of transformation and more specifically for the development of protein antagonists to these TGFs. Efforts have been focused on the purification of members of a specific subset of the TGF family, called TGF beta, which is characterized by a requirement for epidermal growth factor for functional activity and which, because of its presence in all tissues examined thus far, probably has an intrinsic physiological role in normal cell growth. TGF betas are being purified concurrently from murine-sarcoma virus-transformed cells grown in culture and from non-neoplastic murine and bovine kidney. These TGF betas of neoplastic and non-neoplastic derivation and different genomes will then be compared both with regard to biological activity and to chemical composition.